1. Field of the lnvention
This invention relates to a lifting mechanism, and more particularly, to a mechanism for lifting vehicle tires.
2. Problems in the Art
Large and heavy vehicle tires present handling problems. Changing and/or maintenance of these tires is difficult and usually requires specialized equipment.
An example of such tires are the large drive wheels for farm tractors. The particular problem exists in the handling of dual wheels, in that the outside dual wheels of the tractors are added and removed depending on the selected use of the tractor.
Most of the devices known in the art which attempt to help with handling large and heavy tires either utilize a framework to cradle the tire or have some type of means to grasp the outer perimeter of the tire. Once cradled or grasped, the tire thus being supported, can either be moved, raised or lowered.
Problems and deficiencies do exist with these devices. For the cradling devices, the vehicle itself must be jacked up a sufficient height to, at a minimum, equal the level of the tire as it sits in its lowest position in the cradle. For large and heavy vehicles, such as farm tractors, to which the tires belong, it is advantageous to have to raise the vehicle as little as possible. The cradle mechanisms also require supplemental supporting structure to keep the tire upright and secure. This additionally means that the raising and lowering mechanism is fairly complicated and requires structure additional to the holding or cradling structure.
The perimeter grasping devices many times require intricate complicated grasping structure to insure secure holding of heavy, large tires. The special nature and very large diameter of farm tractor drive wheels makes perimeter grasping devices particularly unsatisfactory. The raised tread and the extreme size and weight of a tractor drive wheel would not favor such devices. Maintenance and repair of tires usually requires some rotation of the tire, whether it be for checking the tire or finding and repairing certain locations on the tire. Similarly, adding or removing a tire usually requires either some rotation of the tire or the hub to match the studs with the rim holes. The cradling or perimeter grasping devices do not adequately allow such rotation and it is particularly advantageous for such to be able to occur.
It is therefore an object of the invention to provide a mechanism for lifting vehicle tires which allows rotation of the tire while being lifted and supported by the mechanism.
A further object of this invention is to provide a mechanism for lifting vehicle tires which lifts and supports the tire by contacting the interior rim of the tire.
A further object of this invention is to provide a mechanism for lifting vehicle tires wherein the only points of contact with the tire are on the tire's interior rim.
Another object of this invention is to provide a mechanism for lifting vehicle tires which requires minimal raising of the vehicle itself to remove or add the tire from or to the vehicle.
Another object of this invention is to provide a mechanism for lifting vehicle tires which is adaptable to many different sizes of vehicle tires.
A further object of this invention is to provide a mechanism for lifting vehicle tires which is uncomplicated in structure, economical, and efficient.
Another object of this invention is to provide a mechanism for lifting vehicle tires which allows selective lifting, lowering, supporting, rotating, and transport of vehicle tires.
A further object of this invention is to provide a mechanism for lifting vehicle tires which is easily movable and maneuverable along the ground.
These and other objects, features and advantages of the invention will become apparent with reference to the accompanying specification including the drawings.